「リクエストが多すぎます」というエラーで目が覚めた

I’ve been experiencing this recently as well. Our forum is private (you have to be logged in to see any of it) so that “getting clobbered by a lot of users” is not a plausible scenario. We only have a few hundred users in total, and only a fraction of that would visit the site on a daily basis. How else can I troubleshoot this?